Fluid pressure devices

ABSTRACT

The present invention is concerned with fluid pressure pumps or motors of the type having a rotatable cylinder and a plurality of reciprocal pistons which abut a thrust plate inclined to the axis of rotation of the barrel. In order, among other things, to enhance such abutment a fluid pressure device of the invention is so constructed that the barrel is connected to a port plate by a plurality of sleeves in each of which sleeves is reciprocally mounted a said piston. Sealing means are provided between each sleeve and the port plate and in a preferred embodiment the port plate is associated with a stationary valve plate.

United States Patent [72] lnventor Harold George Oram 285 l-langletonRoad, Hove 4, Sesex, England [211 App]. No. 826,504 [22] Filed May 21,1969 [45] Patented Aug. 24, 1971 [32] Priority May 24, 1968 [33] GreatBritain [31 24,951/68 s41 FLUID PRESSURE DEVICES 2 Claims, 1 DrawingFig.

[52] 11.8. C1 91/499 [51] lnt.Cl F0411 H02 [50] FieldoiSearch 103/162;230/178; 91/499 [56] References Cited UNITED STATES PATENTS 2,206,3057/1940 Rose et a1. 103/162 3,007,420 11/1961 Budzich 103/162 3,285,19311/1966 Jeannin. 103/162 3,295,457 1/1967 Oram 103/162 v FORElGN PATENTS656,487 6/1961 Great Britain 103/162 713,659 8/1931 France 103/162Primary ExaminerWilliam L. Freeh Attorney-Cullen, Sloman & CantorABSTRACT: The present invention is concerned with fluid pressure pumpsor motors of the type having a rotatable cylinder and a plurality ofreciprocal pistons which abut a thrust plate inclined to the axis ofrotation of the barrel. In order, among other things, to enhance suchabutment a fluid pressure device of the invention is so constructed thatthe barrel is connected to a port plate by a plurality of sleeves ineach of which sleeves is reciprocally mounted a said piston. Sealingmeans are provided between each sleeve and the port plate and in apreferred embodiment'the port plate is associated with a stationaryvalve plate.

FLUID PRESSURE DEVICES The present invention relates to so-calledaxial-in-line' fluid pressure devices such as fluid pressure developingunits, i.e. pumps, or fluid pressure operated motors.

Such devices generally comprise a rotatable cylinder barrel with aplurality of axial cylinders therein, each cylinder housing a reciprocalpiston with a shoe so arranged as to abut a thrust plate which isinclined to the axis of rotation of the cylinder barrel.

It is known that, e.g. when a device of this type is started, it isnecessary to bias the cylinder barrel towards a stationary valve plateand to bias the pistons and shoes towards the thrust plate. It isalsoknown to be necessary to counter the cantilever action of the pistonswhich tends to tilt the cylinder barrel and cause separation of thecylinder barrel from the valve plate.

In accordance with prior proposals split cylinder barrels have beenutilized with pistons reciprocating within the barrel and sleevesconnecting the barrel to a port plate. However, such devices are not inall respects satisfactory and it is an object of the present inventionto provide a fluid pressure device, e.g. a pump or motor, with meanswhereby the dynamic response of said port plate is enhanced by theimproved maintenance of its abutment with a said valve plate. It isafurther object to provide an economically priced unit, economy folvmounted within each said sleeve and engaging by one of its ends aninclined stationary thrust plate, and sealing means being providedbetween each said sleeve and the port plate at its region of associationtherewith;

Advantageously the device comprises a body formed in three parts, thethree parts being releasably interengageable by screw means. This, ofcourse, facilitates disassembly.

These and other objects of the invention will be clear from thefollowing description, given with reference to the accompanying drawingwhich is by way of example and in which there is shown in axial sectiona fluid pressure device according to the present invention.

Thus there is shown in the drawing a pump or motor of the axialin-linepiston type as generally referred to above and as illustrated the pumpcomprises a body formed from three parts, being a main body part 2, afirst cover part 1 and a second cover part 3; the said partsare heldtogether by bolts 23 and 24.

As shown, gaskets 26 are provided between the parts 1, 2 and 3 for thepurpose of sealing their abutment surfaces and alignment of the threeparts is obtained by locating shoulder screws (not shown). The part 1 isprovided with a register diameter and flange for mounting purposes.

A shaft 6, provided with a driving key 21, is supported within the pumpbody by bearings 16 and 4 circlips 19 and 20 are provided to limit theaxial movement of the shaft 6. A suitable seal 5 is provided for sealingpurposes. The shaft 6 is also provided with external splines 6a and thesaid splines engage internal splines formed in a collar 10, a cylinderbarrel 11 and a port plate 14. Such engagement is for mutual drivingpurposes and to achieve alignment between opposing bores 11a and 140formed in said latter members respectively.

The port plate 14 is also provided with a plurality of arcuate ports 14bwhich coincide axially with the said bores 14a therein, each said bore14a receiving a sleeve 12 which is also received as a fit in a saidopposing'bore 11a. As shown, each 'sleeve 12 slidably houses a piston 8.As is also shown, the

pistons 8 each have a spherical end 8a onto which'is swaged a shoe 8b,the said shoes 8b being slidable over an inclined stationary thrustplate 7 and constrained by a shoe plate 9 itself biassed by forcesexerted by a spring 13 via the cylinder barrel.

1 1, and collar 10. Such biassing results because the member is slidablealong the shaft 6 as far as the collar 10.

The thrust plate 7 is suitably located by one or more pins 22 andconveniently, a washer 17 and a circlip 18 are provided to restrictaxial movement of all the parts slidably mounted on the shaft 6.

As indicated in the drawing the spring 13 abuts at one end on thecylinder port plate 14 and thus also exerts a force on the said portplate so as to bias it against a valve plate '15 pinned at 15a to thepart 3 and so constructed as to comprise two kidney-shaped parts of typewell'known in the art. Thus, as a result of such spring biassingtheplate 14 is driven against the plate 15, the barrel 11 is biassedagainst the collar 10, and the shoe plate 9 is biassed onto the shoes 8bwhich are slidable on the thrust plate 7. a

As will now be evident, because of the low mass and inertia of the portplate 14, the latter will tend to remain in contact with the valve plate15, being independent of shaft deflection and barrel movement caused bythe cantilever action of the pistons 8 on the inclined thrust plate 7.Furthermore, the sleeves 12 are slidable in the barrel 11, and their fitin plate 14 permits of some flexibility.

By removal of the bolts 23 from the part 1 it will be possible to removevery readily the shaft 6, and all its associated rotatable parts, fromthe parts 2 and 3.

Various modifications of the invention are, of course, possible withinthe scope of the invention as defined by the appended claims.

Thus, each sleeve 12, where it extends into the cylinder port plate 14,may be surrounded by a sealing ring.

It will be appreciated that the helical spring 13 may be replaced by aplurality of springs extending in a direction parallel to the axis ofthe shaft 6.

It will also be appreciated that the collar 10 and the associatedspherical or conical bore in the shoe plate 9 are by way of example onlyand any other suitable assembly may be utilized;

It will also be appreciated that instead of the splines 60 there may beone or more driving keys.

If desired the stationary valve plate 15 may be eliminated and the portplate 14 may bear directly on the cover 3.

I claim What I claim is:

1. A fluid pressure device of the axial-in-line type comprising acylindrical housing; a first closure member disposed at one end of saidhousing, a second closure member disposed at the opposite end of saidhousing; a driven shaft extending axially through said housing rotatablysupported in said first and said second closure members; a driven membersupported 0 said shaft within said cylindrical housing for rotation withsaid shaft; a port plate securely attached to said second closure memberin sealing engagement therewith; a radially inclined cam plate attachedto said first closure member surrounding said shaft; said second closuremember having an inlet port and an outlet port; a plurality ofcommunicating ports provided in said port plate communicating with saidinlet and said outlet respectively; said driven member having a flangeportion provided with a plurality of apertures therethrough in parallelalignment with said shaft; a plurality of sleeve members disposed withinsaid apertures for extension therefrom towards said port plate, each ofsaid sleeve members having a reduced diameter end portion; said portplate being provided with counterbores substantially corresponding insize to said reduced diameter end portions of said sleeves and inaxially aligned communication with said ports in said port plate, eachof said sleeves being adapted to receive in reciprocable relationship apiston member, the outer end ofsaid piston member being universallyattached in radially spaced relationship to a thrust plate surroundingsaid shaft secured to the driven member; said thrust plate beingmaintained in frictional engagement against said radially inclined camplate within said housing so that upon rotation of said shaft withinsaid housing said thrust plate will be forced to rotate along saidinclined cam plate to thereby successively reciprocate the plurality ofpiston members into and out of a respective sleeve associated with saidpiston member, and resilient expansion means disposed between saiddriven member and said port plate around said shaft to constantly urgesaid port plate into engagement against said second closure member forsealing engagement therewith and to urge said driven member into drivingengagement against said inclined cam plate.

2. A fluid pressure device of the axial-in-line type comprising acylindrical housing; a first closure member disposed at one end of saidhousing, a second closure member disposed at the opposite end of saidhousing; a driven shaft extending axially through said housing rotatablysupported in said first and said second closure members; a driven membersupported on said shaft within said cylindrical housing for rotationwith said shaft; a port plate securely attached to said second closuremember in sealing engagement therewith; a radially inclined cam plateattached to said first closure member surrounding said shaft; saidsecond closure member having an inlet port and an outlet port; aplurality of communicating ports provided in said port platecommunicating with said inlet and said outlet respectively; said drivenmember having a flange portion provided with a plurality of aperturestherethrough in parallel alignment with said shaft; a plurality ofsleeve members disposed within said apertures for extension therefromtowards said port plate, each of said sleeve members having a reduceddiameter end portion; said port plate being provided with counter-boressubstantially corresponding in size to said reduced diameter endportions of said sleeves and in axially aligned communication with saidports in said-port plate, each of said sleeves being adapted to receivein reciprocable relationship a piston member, the outer end of saidpiston member being universally attached in radially spaced relationshipto a thrust plate surrounding said shaft secured to the driven member;said thrust plate being maintained in frictional engagement against saidradially inclined cam plate within said housing so that upon rotation ofsaid shaft within said housing said thrust plate will be forced torotate along said inclined cam plate to thereby successively reciprocatethe plurality of piston members into and out of a respective sleeveassociated with said piston member; resilient expansion means disposedbetween said driven member and said port plate around said shaft toconstantly urge said port plate into engagement against said secondclosure member for sealing engagement therewith and said driven memberinto driving engagement against said inclined cam plate; and said portplate and said driven member being coaxially attached to said drivenshaft for conjoint rotation therewith by means of splines to therebymaintain said sleeves in parallel aligned relationship with said drivenshaft. 1

1. A fluid pressure device of the axial-in-line type comprising acylindrical housing; a first closure member disposed at one end of saidhousing, a second closure member disposed at the opposite end of saidhousing; a driven shaft extending axially through said housing rotatablysupporteD in said first and said second closure members; a driven membersupported on said shaft within said cylindrical housing for rotationwith said shaft; a port plate securely attached to said second closuremember in sealing engagement therewith; a radially inclined cam plateattached to said first closure member surrounding said shaft; saidsecond closure member having an inlet port and an outlet port; aplurality of communicating ports provided in said port platecommunicating with said inlet and said outlet respectively; said drivenmember having a flange portion provided with a plurality of aperturestherethrough in parallel alignment with said shaft; a plurality ofsleeve members disposed within said apertures for extension therefromtowards said port plate, each of said sleeve members having a reduceddiameter end portion; said port plate being provided with counterboressubstantially corresponding in size to said reduced diameter endportions of said sleeves and in axially aligned communication with saidports in said port plate, each of said sleeves being adapted to receivein reciprocable relationship a piston member, the outer end of saidpiston member being universally attached in radially spaced relationshipto a thrust plate surrounding said shaft secured to the driven member;said thrust plate being maintained in frictional engagement against saidradially inclined cam plate within said housing so that upon rotation ofsaid shaft within said housing said thrust plate will be forced torotate along said inclined cam plate to thereby successively reciprocatethe plurality of piston members into and out of a respective sleeveassociated with said piston member, and resilient expansion meansdisposed between said driven member and said port plate around saidshaft to constantly urge said port plate into engagement against saidsecond closure member for sealing engagement therewith and to urge saiddriven member into driving engagement against said inclined cam plate.2. A fluid pressure device of the axial-in-line type comprising acylindrical housing; a first closure member disposed at one end of saidhousing, a second closure member disposed at the opposite end of saidhousing; a driven shaft extending axially through said housing rotatablysupported in said first and said second closure members; a driven membersupported on said shaft within said cylindrical housing for rotationwith said shaft; a port plate securely attached to said second closuremember in sealing engagement therewith; a radially inclined cam plateattached to said first closure member surrounding said shaft; saidsecond closure member having an inlet port and an outlet port; aplurality of communicating ports provided in said port platecommunicating with said inlet and said outlet respectively; said drivenmember having a flange portion provided with a plurality of aperturestherethrough in parallel alignment with said shaft; a plurality ofsleeve members disposed within said apertures for extension therefromtowards said port plate, each of said sleeve members having a reduceddiameter end portion; said port plate being provided with counterboressubstantially corresponding in size to said reduced diameter endportions of said sleeves and in axially aligned communication with saidports in said port plate, each of said sleeves being adapted to receivein reciprocable relationship a piston member, the outer end of saidpiston member being universally attached in radially spaced relationshipto a thrust plate surrounding said shaft secured to the driven member;said thrust plate being maintained in frictional engagement against saidradially inclined cam plate within said housing so that upon rotation ofsaid shaft within said housing said thrust plate will be forced torotate along said inclined cam plate to thereby successively reciprocatethe plurality of piston members into and out of a respective sleeveassociated with said piston member; resilient expansion means disposedbetween said drIven member and said port plate around said shaft toconstantly urge said port plate into engagement against said secondclosure member for sealing engagement therewith and said driven memberinto driving engagement against said inclined cam plate; and said portplate and said driven member being coaxially attached to said drivenshaft for conjoint rotation therewith by means of splines to therebymaintain said sleeves in parallel aligned relationship with said drivenshaft.